Delta Air Lines has finished off a $3.5 million renovation of its aging airport control center, a crucial part of its operations at the Minneapolis-St. Paul International Airport.

The facility acts as a command center for Delta's MSP operations, where staff members communicate with pilots, baggage handlers, gate agents and workers that fuel and stock planes with food. Any miscommunication with the center could cause flight delays.

It is common for major airlines to have their own airport control center at their hubs. The center is distinct from the airport's air traffic control tower, which guides planes in and out of the airport.

Delta, the Twin Cities' dominant air carrier, bought new equipment for the center, getting rid of bulky 1980s-era machines. Now, workers use sleek touch screens in roomier workstations. Radio communications between Delta workers on the ground and those in the center are no longer garbled.

"In a geeky kind of way, it's kind of exciting," said Jeff Hart, general manager of hub operations.

Delta says the new equipment saves time for its staff. Control center employees no longer have to rush over to another side of the work area to communicate with colleagues. They can use the intercom on the new machines.

"It's a lot faster," said tower coordinator Isa Erickson. "You can get in touch with people quicker."

Time management is crucial when airlines are trying to reduce costs. The center's employees can redirect flights to other gates if there are delays, which can reduce the likelihood of idle planes with passengers. Planes sitting on the runway burn $21 worth of fuel per minute, said Bob Herbst, founder of AirlineFinancials.com.

"Every single minute they can save getting that airplane to the gate or off of the gate, adds up really quick," Herbst said.

The center was built in 1988 by Northwest Airlines. Delta acquired Northwest in 2008, and last fall Delta approved the renovation.

Hart said the investment shows Delta's commitment to the Twin Cities. Delta has made other significant changes at MSP in recent years, including updating its Sky Club, adding new restaurants andinstalling more self-service kiosks at the airport.